Efficacy of newer insecticides against Agrotis ipsilon Hufnagel in cabbage and its influence on soil microbial dynamics

The study was conducted to assess the effectiveness of four newer insecticides in reducing the infestation of Agrotis ipsilon in cabbage and to determine its impact on soil biological health. Among all the insecticides, the maximum per cent reduction of A. ipsilon was observed in the plots treated with chlorantraniliprole 0.4 GR @100 g a.i ./ha followed by imidacloprid @ 300 g a.i ./ha which was statistically at par with clothianidin @120 g a.i ./ha. Soil microbial population analysis revealed a decrease in both bacterial and fungal colonies in the treated plots compared to control, with chlorantraniliprole 0.4 GR-treated plots maintaining the highest microbial populations, followed by clothianidin 50 WDG. Both PME and FDA activity in treated soils significantly decreased relative to the control. Chlorantraniliprole 0.4 GR-treated plots recorded the highest PME and FDA activity, followed by clothianidin 50 WDG and thiamethoxam 25 WG. The greatest reductions in microbial populations, PME and FDA activity were observed at 15 DAS, but these parameters gradually recovered by 30 and 45 DAS, indicating soil resilience to the insecticides. These findings highlight chlorantraniliprole 0.4 GR as an effective and economically viable solution for managing A. ipsilon in cabbage while minimizing long-term adverse effects on the soil ecosystem.